The acceptance of enzyme catalyzed oxidation and reduction reactions in organic synthesis has been slowed by the expense of the nicotinamide cofactors required by many of these enzymes.
Nicotinamide Adenine Dinucleotide (NAD), for example, is a cofactor which is useful in a variety of enzyme catalyzed reactions, such as producing optically active alcohols, synthesizing carbohydrates, synthesizing fine chemicals, producing aldehydes and carboxylic acids, functionalizing hydrocarbons, and producing amino acids.
NAD is manufactured almost exclusively by a process involving the fermentation of yeast. It presently requires approximately 1 lb. of yeast to manufacture one gram of NAD. The cost of manufacturing is approximately $1.60 per gram.
A typical industrial fermentation process for NAD is described in Kornberg in Vol. 3 of Methods of Enzymology pgs. 876-879 (1957). In the Kornberg fermentation process starch-free bakers yeast is dissolved in boiling water. After removal of other substances from the extract by basic lead acetate, silver nitrate is added and the preparation is allowed to settle over night. The precipitate is collected and decomposed with hydrogen sulfide. The NAD is obtained as the free acid by precipitation with acetone. Further purification is achieved by anion exchange chromatography.
NAD can also be synthesized from nicotinamide mononucleotide (NMN). However, NMN is a very difficult intermediate to obtain. For this reason non-fermentation processes for NAD have been uncompetitive. The conventional method for synthesizing NMN was reported by Jeck in Vol. 42 of the Federation of European Biochemists Society Letters pg. 161 (1974). The basic problem with NMN synthesis is that it must be derived from a beta-ribofuranose moiety. In the conventional synthesis techniques, as reported by Jeck article, various protecting groups were necessary to hold the ribose moiety in the furanose form. Moreover, in the Jeck technique, it is necessary to phosphorylate the beta-nicotinamide riboside as a final step in converting it into NMN. This addition of a phosphate group is a difficult procedure and the overall yields of NMN are quite low.
Additionally, the Jeck technique does not produce ribosylamine-5-phosphate (rA-5-P) as a chemical intermediate. Such an intermediate, itself, would also be valuable. rA-5-P and other 1-amino sugar phosphates can be used in principle to produce a variety of antibiotic and antiviral agents. For example, rA-5-P can be used in the manufacture of ribavirin, an antiviral agent of similar chemical structure.
Attention is directed to an article by the inventors and their colleagues entitled "Synthesis of Nicotinamide Adenine Dinucleotide (NAD) from Adenosine Monophosphate (AMP)" published in Vol. 102 of the Journal of the American Chemical Society, pgs. 7805-7806 (Dec. 17, 1980) and the references cited therein, all of which is hereby incorporated by reference.
There exist a need for a practical non-fermentation route to manufacture nicotinamide cofactors such as NAD, dihydro NAD (NADH), NAD phosphate (NADP) and dihydro NAP phosphate (NADPH). Moreover, there exist a need for more efficient methods of producing 1-amino sugar phosphates.